Ultrasound and Photoacoustic Guided Tissue Temperature Mapping during Ablation Therapies

Abstract

Successful laser ablation treatment procedures require the accurate placement of the ablation catheter tip within the diseased tissue, real-time tissue temperature monitoring, and estimating the heat diffusion from the catheter tip to the surrounding tissues. Poor catheter tip visualization due to ultrasound (US) imaging artifacts, poor contrast, and lack of real-time thermometry and heat diffusion maps lead to unsafe or incomplete treatments. Our previous in vivo animal studies validated the real-time catheter tip tracking and thermometry capabilities of photoacoustic (PA) imaging. During laser ablation studies, the continuous wave (CW) laser light energy exiting the catheter tip is converted into heat and diffused into the surrounding tissue. Using US imaging and tissue classification, it is possible to develop a tissue heat diffusion map. PA measures the temperature at the catheter tip. Therefore, the combination of US and PA imaging can provide real-time tissue temperature maps that could be overlaid over US structural images and can provide effective treatments.